Equipment and method for detecting airtightness of sealing opening of packaging bag

Abstract

The invention relates to the technical field of air tightness detection, in particular to equipment and a method for detecting the air tightness of a sealing opening of a packaging bag. Comprising an air tightness detector, a liquid bin, a top cover assembly detachably installed on the liquid bin, an inflation assembly installed on the top cover assembly, a counterweight assembly detachably installed on a packaging bag and an air needle installed on the counterweight assembly. Gas flows into or out of the packaging bag through the gas needle; according to the invention, by installing the counterweight assembly on the packaging bag, before the packaging bag is inflated, the packaging bag can be fully suspended in water and keeps a certain distance with the baffle plate above, so that air leakage outside the water body is avoided, and the bubble floating distance is increased due to no shielding of the baffle plate; bubbles and source points thereof can be observed and tracked conveniently.

Description

Technical Field

[0001] The present invention relates to the technical field of airtightness detection, and particularly to an apparatus and method for detecting the airtightness of the seal of a packaging bag. Background Art

[0002] The bubble method for detecting airtightness is a conventional means for detecting packaging bags. Therefore, in the prior art, there is a special detector for detecting the airtightness of packaging bags. After connecting the packaging bag to an inflation needle and placing it in water, the detector inflates the packaging bag until a preset pressure value is reached, then stops inflation, and observes for a period of time to see if any bubbles emerge. If bubbles emerge, the detection is stopped, indicating that the airtightness of the packaging bag is unqualified. This detection method has a simple principle and is very intuitive.

[0003] When using an airtightness detector to sample and test the airtightness of the seal of a packaging bag, after placing the packaging bag in water, it is necessary to use a baffle to cover it to prevent the packaging bag from floating out of the water under the buoyancy of the water body. Otherwise, if the leakage point is above the water surface, no bubbles can be observed and the airtightness cannot be detected. Although this method is relatively simple and convenient, the packaging bag being tested is filled with gas and will float under the baffle due to the buoyancy of the water body. If the packaging bag is in close contact with the baffle, some bubbles may be trapped by the baffle or their paths may be changed, affecting the accuracy of observation. Even if there is a leakage point at the seal or other parts of the packaging bag, the generated bubbles float upward, but due to the obstruction of the baffle, the floating distance is too short, and the baffle blocks the line of sight, making it difficult to observe the bubbles.

[0004] Therefore, in view of the above problems, a detection device can be designed to appropriately increase the distance between the packaging bag and the baffle, reduce the interference of the baffle on the generation and floating of bubbles, and make the bubbles rise along the natural path, making it easier to observe. Summary of the Invention

[0005] In order to overcome the problem that bubbles are not easily observable when detecting the airtightness of a packaging bag because it is in close contact with the baffle.

[0006] The technical solution of the present invention is as follows: An apparatus for detecting the airtightness of the sealing of a packaging bag, comprising an airtightness detector, a liquid chamber, a top cover assembly detachably mounted on the liquid chamber, an inflation assembly mounted on the top cover assembly, a counterweight assembly detachably mounted on the packaging bag, and an air needle mounted on the counterweight assembly. The airtightness detector is used to input or extract gas into the inflation assembly. The air needle is communicated with the inflation assembly, and gas can flow between the inflation assembly and the air needle. The gas flows into or out of the packaging bag through the air needle. When the counterweight assembly is mounted on the packaging bag, the packaging bag can be suspended at a preset position in the liquid chamber; when the airtightness detector inputs gas into the inflation assembly, the gas in the inflation assembly flows into the packaging bag through the air needle; when the airtightness detector extracts gas from the inflation assembly, the gas in the packaging bag flows into the inflation assembly through the air needle; a liquid filling assembly is mounted on the top cover assembly, a counterweight liquid is provided in the liquid filling assembly, the liquid filling assembly is communicated with the counterweight assembly, and the counterweight liquid can flow between the liquid filling assembly and the counterweight assembly; when gas flows into the packaging bag through the air needle, the counterweight liquid flows from the liquid filling assembly into the counterweight assembly; when gas flows out of the packaging bag through the air needle, the counterweight liquid flows from the counterweight assembly into the liquid filling assembly.

[0007] Preferably, the top cover assembly includes a sealing plug detachably mounted on the liquid chamber, a baffle plate, and a plurality of connecting frames fixedly connected between the sealing plug and the baffle plate. A plurality of holes are provided on the baffle plate. When the sealing plug is mounted on the liquid chamber, the bottom surface of the baffle plate is below the water surface in the liquid chamber.

[0008] Preferably, the inflation assembly includes an air chamber mounted on the sealing plug, an intake pipe with one end connected to the air chamber, an upper shaft plug movably connected in the air chamber, a return spring mounted in the air chamber, and an air delivery pipe with one end connected to the air chamber. The upper shaft plug divides the air chamber into two independent spaces. The other end of the intake pipe is connected to the airtightness detector, and gas flows between the airtightness detector and one of the independent spaces in the air chamber through the intake pipe. One end of the return spring is connected to the inner wall of the air chamber, and the other end is connected to the upper shaft plug. The other end of the air delivery pipe is connected to the air needle, and gas flows between the packaging bag and the other independent space in the air chamber through the air delivery pipe and the air needle. When gas flows into one of the independent spaces in the air chamber through the intake pipe, the upper shaft plug moves downward and controls the gas in the other independent space in the air chamber to flow into the packaging bag through the air delivery pipe and the air needle.

[0009] Preferably, the counterweight assembly includes a clamping plate detachably mounted on the packaging bag and a counterweight block mounted on the clamping plate. The gravity of the counterweight block is greater than the buoyancy of the packaging bag.

[0010] Preferably, the liquid filling assembly includes a liquid chamber installed on the sealing plug, a lower shaft plug movably connected in the liquid chamber, an infusion tube with one end connected to the liquid chamber, and an electric valve installed on the infusion tube. The lower shaft plug divides the liquid chamber into two independent spaces. The other end of the infusion tube is connected to the counterweight block. The lower shaft plug is fixedly connected to the upper shaft plug. The upper shaft plug is used to drive the lower shaft plug to move in the liquid chamber. The electric valve is used to open or close the infusion tube. The counterweight liquid flows through the infusion tube in one of the independent spaces between the counterweight block and the liquid chamber. When the upper shaft plug drives the lower shaft plug to move downward, the counterweight liquid flows into the counterweight block through the infusion tube.

[0011] Preferably, a pressing assembly is installed on the air inflation assembly, an air hood and a return assembly are installed on the top cover assembly. The return assembly is communicated with the air hood and the liquid filling assembly. The pressing assembly is used to control the flow of gas between the air hood and the return assembly. A positioning assembly is movably connected to the top cover assembly. The liquid return assembly is used to drive the positioning assembly to move in a preset direction. When the airtightness detector inputs gas into the air inflation assembly, the pressing assembly controls the gas in the air hood to flow into the return assembly, and the return assembly drives the positioning assembly away from the center of the packaging bag. When the airtightness detector extracts gas from the air inflation assembly, the pressing assembly controls the gas in the return assembly to flow into the air hood, and the return assembly drives the positioning assembly close to the center of the packaging bag. The pressing assembly includes a traction frame fixedly connected to the upper shaft plug and a pressing plate fixedly connected to the traction frame. The upper shaft plug controls the pressing plate to move in a preset direction through the traction frame.

[0012] Preferably, the return assembly includes an air cylinder installed on the baffle, a gas supply pipe, a gas return pipe with one end connected to the air cylinder, and a plunger movably connected in the air cylinder. The plunger divides the air cylinder into two independent spaces. The other end of the gas supply pipe is connected to the air hood, and the other end of the gas return pipe is connected to the liquid chamber. Gas flows through the gas supply pipe in one of the independent spaces between the air hood and the air cylinder. Gas flows through the gas return pipe in the other independent space between the liquid chamber and the air cylinder. When gas flows through the gas supply pipe in one of the independent spaces between the air hood and the air cylinder, the plunger moves in the air cylinder.

[0013] Preferably, a chute is formed on the baffle, and the positioning assembly is movably connected in the chute. The positioning assembly includes a slider movably connected in the chute, a hanging bracket fixedly connected to the slider, and a positioning rod fixedly connected to the hanging bracket. The slider is fixedly connected to the corresponding plunger. The plunger is used to drive the slider, the hanging bracket and the positioning rod to move along the axis direction of the chute.

[0014] Preferably, a sensor is installed on the air inflation assembly, and a supplementary light is installed on the top cover assembly. The sensor is used to detect the state of the air inflation assembly and send signals to the control unit of the supplementary light and the airtightness detector. The sensor includes a tension sensor installed on the upper shaft plug. The tension sensor is used to detect the tension value of the return spring. When the tension sensor detects that the tension value of the return spring reaches the preset value, the airtightness detector is turned off and the supplementary light is turned on.

[0015] A method for detecting the airtightness of the seal of a packaging bag, using a device for detecting the airtightness of the seal of a packaging bag as described above, includes the following steps:

[0016] S1: The user fills the liquid chamber with clear water meeting the detection requirements of turbidity through the water inlet preset on the sealing plug until the water surface height of the clear water is higher than the height of the baffle;

[0017] S2: Take out the sealing plug and the baffle from the liquid chamber, then clamp and fix the splint at the bottom of the packaging bag, and then insert the air needle into the packaging bag and bond it to the packaging bag through the sealing piece provided on the air needle to seal the puncture point;

[0018] S3: Make the sealed part of the packaging bag face upward, and put the packaging bag together with the counterweight into the liquid cylinder. At this time, the gravity of the counterweight is greater than its own buoyancy and the buoyancy of the packaging bag. Under the action of the gravity of the counterweight, the packaging bag sinks underwater;

[0019] S4: Reinstall the sealing plug and the baffle in the liquid chamber, and align the positioning rod with both sides of the packaging bag to restrict the packaging bag from swinging to both sides under the action of buoyancy. At this time, there is an appropriate height difference between the baffle and the sealed part of the packaging bag;

[0020] S5: According to the airtightness detection test standard of the packaging bag, set the corresponding parameters on the airtightness detector, start the airtightness detector, input gas into one of the independent spaces in the air chamber through the air inlet pipe, make the upper shaft plug move downward against the elastic force of the return spring, push the gas in the other independent space in the air chamber into the air needle through the gas delivery pipe, and then flow into the packaging bag through the air needle to make the packaging bag inflate and expand. At the same time, the buoyancy received by the packaging bag also increases accordingly;

[0021] S6: Synchronously with S5, the upper shaft plug drives the lower shaft plug to move downward at the same time. The lower shaft plug pushes the counterweight liquid in one of the independent cavities in the liquid chamber into the counterweight through the liquid delivery pipe, and the weight of the counterweight increases synchronously to resist the increased buoyancy of the packaging bag;

[0022] S7: Synchronously with S5 and S6, the pressing plate moves downward synchronously under the drive of the upper shaft plug, and generates a squeezing force on the air hood, making the gas in the air hood flow into one of the independent spaces in the liquid cylinder through the air delivery pipe, making the plunger move, and through the connection with the slider, controlling the hanger and the positioning rod to move along the axis direction of the chute, away from the center of the packaging bag. The gas in the other independent space in the liquid cylinder flows into the other independent cavity in the liquid chamber through the return air pipe;

[0023] S8: When the gas pressure in the packaging bag reaches the preset detection pressure, the tension sensor detects that the tension value of the return spring reaches the preset value F1, sends a signal to the airtightness detector to stop injecting gas, and sends a signal to the control unit of the fill light. The fill light is turned on to illuminate the water body in the packaging bag and the liquid storage tank;

[0024] S9: Observe whether bubbles are generated at the sealing position of the packaging bag. After a period of time, if no bubbles are generated, the packaging bag meets the airtightness standard; if bubbles are generated, it does not meet the airtightness standard.

[0025] Advantages of the present invention:

[0026] 1. By installing a weight component on the packaging bag, the packaging bag can fully float in the water before inflation and maintain a certain distance from the upper baffle, preventing air leakage outside the water body. At the same time, without the obstruction of the baffle, the floating distance of the bubbles is increased, facilitating the observation and tracking of the bubbles and their source points;

[0027] 2. When the buoyancy obtained by the packaging bag after inflation resists the gravity of the weight component, it will pull on the bottom of the packaging bag, simulating the stress situation of the packaging bag when storing objects during actual use. The tensile deformation ability of the packaging bag is detected by checking the deformation amount of the bottom of the packaging bag after the airtightness test;

[0028] 3. Through the cooperation of the inflation component and the liquid filling component, the weight of the weight component can be increased synchronously while inflating the packaging bag, avoiding the packaging bag floating due to the buoyancy being greater than the gravity of the weight component during inflation, which has an adverse effect on bubble observation;

[0029] 4. Before inflation, the unfilled packaging bag is sunk underwater through weights and then inflated step by step. This can simplify the experimental process to a certain extent. The unfilled packaging bag is softer and easier to fix its position through the weight component, avoiding unnecessary movement caused by buoyancy changes;

[0030] 5. The packaging bag is fixed by the clamping plate integrated with the weight block to prevent the packaging bag from detaching from the weight block as the buoyancy of the packaging bag increases during inflation;

[0031] 6. The packaging bag can be fixed through the positioning component to prevent the packaging bag from swinging significantly due to water body disturbance, affecting the normal observation of bubbles;

[0032] 7. Through the cooperation of the reflux component and the air hood, the position of the positioning component can be adjusted while inflating the packaging bag, avoiding the positioning component exerting an extrusion force on the expanding packaging bag and causing it to rupture;

[0033] 8. Through the cooperation of the tension sensor and the fill light, the illumination of the inside of the packaging bag and the liquid storage tank starts only when the packaging bag is fully inflated to the detection pressure. This method is more energy-efficient compared to the constantly-on fill light. Description of the Drawings

[0034] Figure 1 Shown is a three-dimensional structural schematic diagram of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0035] Figure 2 Shown is a cross-sectional structural schematic diagram of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0036] Figure 3 Shown is another cross-sectional structural schematic diagram of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0037] Figure 4 Shown is a first structural schematic diagram of the packaging bag assembly of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0038] Figure 5 Shown is a second structural schematic diagram of the packaging bag assembly of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0039] Figure 6 Shown is a schematic diagram of the inflation assembly and the air needle of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0040] Figure 7 Shown is a schematic diagram of the counterweight assembly and the liquid filling assembly of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0041] Figure 8 Shown is a schematic diagram of the baffle of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0042] Figure 9 Shown is a schematic diagram of the pressing assembly, the reflux assembly and the positioning assembly of the device for detecting the airtightness of the packaging bag seal of the present invention;

[0043] Figure 10 Shown is the device for detecting the airtightness of the packaging bag seal of the present invention Figure 3 in which the enlarged schematic diagram at position A;

[0044] Figure 11 Shown is the device for detecting the airtightness of the packaging bag seal of the present invention Figure 2 in which the enlarged schematic diagram at position B;

[0045] Figure 12 Shown is the device for detecting the airtightness of the packaging bag seal of the present invention Figure 3Enlarged schematic diagram at position C in the figure.

[0046] Description of reference numerals in the drawings: 1. Air tightness detector; 2. Liquid storage tank; 501. Air needle; 901. Air hood; 301. Sealing plug; 302. Connecting frame; 303. Baffle; 401. Air cavity; 402. Air inlet pipe; 403. Upper shaft plug; 404. Return spring; 405. Air delivery pipe; 601. Clamp plate; 602. Counterweight; 701. Liquid cavity; 702. Lower shaft plug; 703. Liquid delivery pipe; 704. Electric valve; 801. Traction frame; 802. Pressing plate; 1001. Air cylinder; 1002. Air supply pipe; 1003. Return air pipe; 1004. Plunger; 1101. Slide groove; 1102. Slide block; 1103. Hanging frame; 1104. Positioning rod; 1201. Tensile sensor; 1301. Supplementary light. Specific embodiments

[0047] The present invention will be further described below with reference to the drawings and embodiments.

[0048] Please refer to Figures 1 - 12, the present invention provides an embodiment: a device for detecting the airtightness of the sealing of a packaging bag, including an airtightness detector 1, a liquid storage tank 2, a top cover assembly detachably installed on the liquid storage tank 2, an inflation assembly installed on the top cover assembly, a weight assembly detachably installed on the packaging bag, and an air needle 501 installed on the weight assembly. The airtightness detector 1 is used to input or extract gas into the inflation assembly. The air needle 501 is connected to the inflation assembly, and gas can flow between the inflation assembly and the air needle 501. The gas flows into or out of the packaging bag through the air needle 501. When the weight assembly is installed on the packaging bag, the packaging bag can be suspended at a preset position in the liquid storage tank 2; when the airtightness detector 1 inputs gas into the inflation assembly, the gas in the inflation assembly flows into the packaging bag through the air needle 501; when the airtightness detector 1 extracts gas from the inflation assembly, the gas in the packaging bag flows into the inflation assembly through the air needle 501; a liquid filling assembly is installed on the top cover assembly. The liquid filling assembly is provided with a counterweight liquid, and the liquid filling assembly is connected to the weight assembly, and the counterweight liquid can flow between the liquid filling assembly and the weight assembly; when gas flows into the packaging bag through the air needle 501, the counterweight liquid flows from the liquid filling assembly into the weight assembly; when gas flows out of the packaging bag through the air needle 501, the counterweight liquid flows from the weight assembly into the liquid filling assembly. After fixing the weight assembly to the non-inflated packaging bag, insert the air needle 501 into the packaging bag (note not to pierce the packaging bag), and then put the packaging bag and the weight assembly into the liquid storage tank 2 together. When the gravity of the weight assembly is greater than the sum of its buoyancy and the buoyancy of the packaging bag, the packaging bag will continue to sink and be completely submerged below the water surface (because the buoyancy of the packaging bag is not enough to completely offset the gravity of the weight, the packaging bag will be subjected to a downward pulling force and may be deformed at the connection position with the weight assembly). When the airtightness detector 1 inflates the packaging bag through the inflation assembly and the air needle 501, the liquid filling assembly simultaneously fills the weight assembly with the counterweight liquid (maintaining the state where the gravity of the weight assembly is greater than the sum of its buoyancy and the buoyancy of the packaging bag). In this way, the airtightness of the sealing of the packaging bag under different internal pressure states can be detected according to the different inflation amounts of the packaging bag, and the situation where the gas in the packaging bag changes and causes it to float in the water will not occur.

[0049] Please refer to Figures 1 - 5 , Figure 8 and Figures 11 - 12 , in this embodiment, the top cover assembly includes a sealing plug 301 detachably installed on the liquid storage tank 2, a baffle 303, and a plurality of connecting frames 302 fixedly connected between the sealing plug 301 and the baffle 303. The baffle 303 is provided with a plurality of holes. When the sealing plug 301 is installed on the liquid storage tank 2, the bottom surface of the baffle 303 is below the water surface in the liquid storage tank 2. The sealing plug 301 and the baffle 303 are used to close the upper opening of the liquid storage tank 2. In normal use, the baffle 303 is submerged below the water surface in the liquid storage tank 2, which can prevent the packaging bag from floating above the water surface and ensure that possible leakage points are in the water.

[0050] Please refer toFigures 1 - 11, in this embodiment, the inflation assembly includes an air chamber 401 installed on the sealing plug 301, an air inlet pipe 402 with one end connected to the air chamber 401, an upper shaft plug 403 movably connected in the air chamber 401, a return spring 404 installed in the air chamber 401, and an air delivery pipe 405 with one end connected to the air chamber 401. The upper shaft plug 403 divides the air chamber 401 into two independent spaces. The other end of the air inlet pipe 402 is connected to the airtightness detector 1, and gas flows between the airtightness detector 1 and one independent space in the air chamber 401 through the air inlet pipe 402. One end of the return spring 404 is connected to the inner wall of the air chamber 401, and the other end is connected to the upper shaft plug 403. The other end of the air delivery pipe 405 is connected to the air needle 501, and gas flows between the packaging bag and the other independent space in the air chamber 401 through the air delivery pipe 405 and the air needle 501. When gas flows into one independent space in the air chamber 401 through the air inlet pipe 402, the upper shaft plug 403 moves downward and controls the gas in the other independent space in the air chamber 401 to flow into the packaging bag through the air delivery pipe 405 and the air needle 501; the weight component includes a clamping plate 601 detachably installed on the packaging bag and a weight block 602 installed on the clamping plate 601, and the gravity of the weight block 602 is greater than the buoyancy of the packaging bag;The liquid filling assembly includes a liquid chamber 701 mounted on the sealing plug 301, a lower shaft plug 702 movably connected in the liquid chamber 701, an infusion tube 703 with one end connected to the liquid chamber 701, and an electric valve 704 mounted on the infusion tube 703. The lower shaft plug 702 divides the liquid chamber 701 into two independent spaces. The other end of the infusion tube 703 is connected to the counterweight 602. The lower shaft plug 702 is fixedly connected to the upper shaft plug 403. The upper shaft plug 403 is used to drive the lower shaft plug 702 to move within the liquid chamber 701. The electric valve 704 is used to open or close the infusion tube 703. The counterweight liquid flows through the infusion tube 703 between the counterweight 602 and one of the independent spaces in the liquid chamber 701. When the upper shaft plug 403 drives the lower shaft plug 702 to move downward, the counterweight liquid flows into the counterweight 602 through the infusion tube 703. Start the airtightness detector 1, and input gas into one of the independent spaces in the air chamber 401 through the air inlet pipe 402, so that the upper shaft plug 403 moves downward against the elastic force of the return spring 404, and pushes the gas in the other independent space in the air chamber 401 into the air needle 501 through the air delivery pipe 405, and then flows into the packaging bag through the air needle 501, causing the packaging bag to inflate. At the same time, the buoyancy received by the packaging bag also increases accordingly (according to the buoyancy formula, when the volume of the packaging bag becomes larger, the buoyancy becomes larger). During the movement of the upper shaft plug 403, it drives the lower shaft plug 702 to move in the liquid chamber 701 at the same time. The lower shaft plug 702 pushes the counterweight liquid (a liquid with a density greater than that of water can be selected as the counterweight liquid, such as brine, glycerol or mineral oil) in one of the independent cavities of the liquid chamber 701 into the counterweight 602 through the infusion tube 703 (the electric valve 704 is in the open state). The weight of the counterweight 602 increases synchronously (the volume remains unchanged, the weight increases, and its own buoyancy remains unchanged) to resist the increased buoyancy of the packaging bag. After the packaging bag is inflated to an appropriate amount, turn off the airtightness detector 1 and the electric valve 704, stop filling the gas and the counterweight liquid, and observe whether there are air bubbles floating at the sealing position of the packaging bag.;

[0051] Please refer to Figures 1 - 5 , Figures 8 - 9 and Figures 11 - 12, in this embodiment, a pressing component is installed on the inflation component, an air hood 901 and a reflux component are installed on the top cover component, the reflux component is communicated with the air hood 901 and the liquid filling component, the pressing component is used to control the flow of gas between the air hood 901 and the reflux component, a positioning component is movably connected to the top cover component, and the liquid return component is used to drive the positioning component to move in a preset direction; when the airtightness detector 1 inputs gas into the inflation component, the pressing component controls the gas in the air hood 901 to flow into the reflux component, and the reflux component drives the positioning component away from the center of the packaging bag; when the airtightness detector 1 extracts gas from the inflation component, the pressing component controls the gas in the reflux component to flow into the air hood 901, and the reflux component drives the positioning component close to the center of the packaging bag; the pressing component includes a traction frame 801 fixedly connected to the upper shaft plug 403 and a pressing plate 802 fixedly connected to the traction frame 801, and the upper shaft plug 403 controls the pressing plate 802 to move in a preset direction through the traction frame 801; the reflux component includes an air cylinder 1001 installed on the baffle 303, an air supply pipe 1002 and a return air pipe 1003 with one end connected to the air cylinder 1001, and a plunger 1004 movably connected in the air cylinder 1001. The plunger 1004 divides the air cylinder 1001 into two independent spaces. The other end of the air supply pipe 1002 is connected to the air hood 901, and the other end of the return air pipe 1003 is connected to the liquid cavity 701. Gas flows through the air supply pipe 1002 in one independent space of the air hood 901 and the air cylinder 1001, and gas flows through the return air pipe 1003 in the other independent space of the liquid cavity 701 and the air cylinder 1001. When gas flows through the air supply pipe 1002 in one independent space of the air hood 901 and the air cylinder 1001, the plunger 1004 moves in the air cylinder 1001;A chute 1101 is formed in the baffle 303, and a positioning component is movably connected in the chute 1101. The positioning component includes a slider 1102 movably connected in the chute 1101, a hanging bracket 1103 fixedly connected to the slider 1102, and a positioning rod 1104 fixedly connected to the hanging bracket 1103. The slider 1102 is fixedly connected to the corresponding plunger 1004. The plunger 1004 is used to drive the slider 1102, the hanging bracket 1103 and the positioning rod 1104 to move along the axis direction of the chute 1101. Under the movement control of the upper plug 403, the pressing plate 802 moves synchronously and in the same direction. When the packaging bag is inflated, the pressing plate 802 moves with the upper plug 403 to generate a pressing force on the air hood 901, so that the gas in the air hood 901 flows into one of the independent spaces of the air cylinder 1001 through the air supply pipe 1002, causing the plunger 1004 to move, and through the connection with the slider 1102, controlling the hanging bracket 1103 and the positioning rod 1104 to move along the axis direction of the chute 1101, away from the center of the packaging bag (moving along with the expansion of the packaging bag to prevent resisting the expansion force of the packaging bag). When the airtightness detector 1 extracts the gas in the packaging bag through the inflation component, the pressing plate 802 moves with the upper plug 403 to generate a pulling force on the air hood 901, and the gas in the air cylinder 1001 flows back into the air hood 901, causing the plunger 1004 to move in the other direction, that is, controlling the hanging bracket 1103 and the positioning rod 1104 to move away from the center of the packaging bag (moving along with the contraction of the packaging bag and supporting on both sides of the packaging bag).;

[0052] Please refer to Figures 1 - 3 , Figure 5 , Figure 8 and Figures 11 - 12, in this embodiment, a sensor is installed on the inflation assembly, and a fill light 1301 is installed on the top cover assembly. The sensor is used to detect the state of the inflation assembly and send a signal to the control unit of the fill light 1301 and the airtightness detector 1; the sensor includes a tension sensor 1201 installed on the upper shaft plug 403. The tension sensor 1201 is used to detect the tension value of the return spring 404. When the tension sensor 1201 detects that the tension value of the return spring 404 reaches a preset value, the airtightness detector 1 is turned off and the fill light 1301 is turned on. When the gas pressure in the packaging bag reaches the preset detection pressure (the upper shaft plug 403 moves to a certain preset position), the tension sensor 1201 detects that the tension value of the return spring 404 reaches the preset value F1 (the upper shaft plug 403 generates a corresponding tension on the return spring 404 at this preset position), sends a signal to the airtightness detector 1 to stop injecting gas, and sends a signal to the control unit of the fill light 1301. The fill light 1301 is turned on to illuminate the packaging bag and the water body in the liquid storage tank 2. (In the prior art, a constant light is generally used for supplementary lighting, which needs to be manually turned on and off, and it is impossible to turn on and off in time. Often, the turning-on time is too long, resulting in energy waste. Therefore, the change of the return spring 404 is detected by the tension sensor 1201 to control the automatic turning on and off of the fill light 1301 for lighting, which is more energy-saving).

[0053] Please refer to Figures 1 - 12 , in this embodiment, the present invention provides a method for detecting the airtightness of the seal of a packaging bag, using a device for detecting the airtightness of the seal of a packaging bag as described above, including the following steps:

[0054] S1: The user fills the liquid storage tank 2 with clear water with a turbidity meeting the detection requirements through a water inlet preset on the sealing plug 301 (in actual application, the sealing plug 301 can also be taken out and then filled with water), until the water surface height of the clear water is higher than the height of the baffle 303 (ensuring that the packaging bag will be completely submerged in the water surface after being put into the water);

[0055] S2: Remove the sealing plug 301 and the baffle 303 from the liquid storage chamber 2. Then, clamp and fix the clamping plate 601 at the bottom of the packaging bag (i.e., on the other side relative to the sealing position. During inflation, the buoyancy of the packaging bag will continuously increase, and there is a counterweight 602 on the air needle 501. The directions of the forces on the packaging bag are opposite, which easily causes the air needle 501 to separate from the packaging bag and affect the detection. Therefore, the clamping plate 601 is used here to further fix the air needle 501 and the bottom of the packaging bag, that is, the area where the load is relatively concentrated during the actual use of the packaging bag, and it is not easy to separate. Moreover, the clamping plate 601 should be selected with a relatively wide structure to reduce local stress concentration and avoid damaging the packaging bag. Through the buoyancy pulling effect, the tensile strength of this part of the packaging bag can be detected), and then insert the air needle 501 into the packaging bag (in actual application, a suitable position at the bottom of the packaging bag can be selected to avoid being too close to the sealing position, which may damage the sealing structure during the inflation process or the piercing process), and seal the piercing point by bonding with the sealing piece provided on the air needle 501 (an existing technical means used to seal the possible gaps between the air needle 501 and the packaging bag and can also be used to assist in fixing the air needle 501) on the packaging bag;

[0056] S3: Make the sealing part of the packaging bag face upward, and put the packaging bag together with the counterweight 602 into the liquid cylinder. At this time, the gravity of the counterweight 602 is greater than its own buoyancy and the buoyancy of the packaging bag. Under the action of the gravity of the counterweight 602, the packaging bag sinks underwater;

[0057] S4: Reinstall the sealing plug 301 and the baffle 303 in the liquid storage chamber 2, and align the positioning rod 1104 with both sides of the packaging bag (both sides of the expanded surface of the packaging bag) to limit the packaging bag from swinging to both sides under the action of buoyancy. At this time, there is a suitable height difference between the baffle 303 and the sealing part of the packaging bag (in actual application, according to the buoyancy formula: F buoy = V displacement × g × ρ, where V displacement is the volume of the displaced water, g is the acceleration due to gravity, and ρ is the density of water, it is necessary to design the volume and weight of the counterweight 602 to balance the influence of the buoyancy of the packaging bag);

[0058] S5: According to the airtightness detection test standard of the packaging bag, set the corresponding parameters on the airtightness detector 1 (existing technology, the injection speed, pressure, and inflation volume of the gas can be adjusted). Start the airtightness detector 1, input gas into one of the independent spaces in the air chamber 401 through the air inlet pipe 402, make the upper shaft plug 403 move downward against the elastic force of the return spring 404, push the gas in the other independent space in the air chamber 401 into the air needle 501 through the air delivery pipe 405, and then flow into the packaging bag through the air needle 501, making the packaging bag inflate and expand. At the same time, the buoyancy received by the packaging bag also increases accordingly;

[0059] S6: Synchronous with S5, the upper shaft plug 403 drives the lower shaft plug 702 to move downward simultaneously. The lower shaft plug 702 pushes the counterweight liquid (a liquid with a density greater than that of water can be selected as the counterweight liquid, such as brine, glycerol or mineral oil) in one of the independent cavities of the liquid chamber 701 into the counterweight block 602 through the infusion tube 703. The weight of the counterweight block 602 increases synchronously to resist the increased buoyancy of the packaging bag (it should be noted that in practical applications: control the increased gravity of the counterweight block 602 to be greater than or equal to the increased buoyancy of the packaging bag within the same time to prevent the packaging bag from floating due to excessive buoyancy. The tensile deformation ability of the packaging bag under unbalanced force can also be detected in this way);

[0060] S7: Synchronous with S5 and S6, under the drive of the upper shaft plug 403, the pressure plate 802 moves downward synchronously and generates a squeezing force on the air hood 901, causing the gas in the air hood 901 to flow into one of the independent spaces of the air cylinder 1001 through the air supply pipe 1002, causing the plunger 1004 to move. Through the connection with the slider 1102, the hanging bracket 1103 and the positioning rod 1104 are controlled to move along the axis direction of the sliding groove 1101, away from the center of the packaging bag. The gas in the other independent space of the air cylinder 1001 flows into the other independent cavity of the liquid chamber 701 through the return air pipe 1003 (the return air pipe 1003 is mainly used to balance the pressure change between the liquid chamber 701 and the air cylinder 1001. In actual use, the return air pipe 1003 can also be cancelled, and the water in the liquid storage 2 can be used to flow into the air cylinder 1001 and the liquid chamber 701 to balance the pressure);

[0061] S8: When the gas pressure in the packaging bag reaches the preset detection pressure, the tensile force sensor 1201 detects that the tensile force value of the return spring 404 reaches the preset value F1, sends a signal to the airtightness detector 1 to stop injecting gas, and sends a signal to the control unit of the supplementary light 1301. The supplementary light 1301 is turned on to illuminate the packaging bag and the water body in the liquid storage 2;

[0062] S9: Observe whether bubbles are generated at the sealing position of the packaging bag. After a period of time, if no bubbles are generated, the packaging bag meets the airtightness standard. If bubbles are generated, it does not meet the airtightness standard (after taking out the packaging bag, measure the bottom deformation amount of the packaging bag with a measuring tool to detect its tensile ability).

Claims

1. An apparatus for detecting the airtightness of the sealed opening of a packaging bag, characterized in that: It includes an airtightness detector (1), a liquid storage tank (2), a top cover assembly detachably installed on the liquid storage tank (2), an inflation assembly installed on the top cover assembly, a counterweight assembly detachably installed on the packaging bag, and an air needle (501) installed on the counterweight assembly. The airtightness detector (1) is used to input or extract gas into the inflation assembly. The air needle (501) is communicated with the inflation assembly, and gas can flow between the inflation assembly and the air needle (501). The gas flows into or out of the packaging bag through the air needle (501). When the counterweight assembly is installed on the packaging bag, the packaging bag can be suspended at a preset position in the liquid storage tank (2). When the airtightness detector (1) inputs gas into the inflation assembly, the gas in the inflation assembly flows into the packaging bag through the air needle (501); when the airtightness detector (1) extracts gas from the inflation assembly, the gas in the packaging bag flows into the inflation assembly through the air needle (501). A liquid filling assembly is installed on the top cover assembly. The liquid filling assembly is provided with a counterweight liquid, and the liquid filling assembly is communicated with the counterweight assembly. The counterweight liquid can flow between the liquid filling assembly and the counterweight assembly. When gas flows into the packaging bag through the air needle (501), the counterweight liquid flows from the liquid filling assembly into the counterweight assembly; when gas flows out of the packaging bag through the air needle (501), the counterweight liquid flows from the counterweight assembly into the liquid filling assembly.

2. The device for detecting the airtightness of the seal of a packaging bag according to claim 1, wherein: The top cover assembly includes a sealing plug (301) detachably installed on the liquid storage tank (2), a baffle (303), and a plurality of connecting frames (302) fixedly connected between the sealing plug (301) and the baffle (303). The baffle (303) is provided with a plurality of holes. When the sealing plug (301) is installed on the liquid storage tank (2), the bottom surface of the baffle (303) is below the water surface in the liquid storage tank (2).

3. The device for detecting the airtightness of the seal of a packaging bag according to claim 2, characterized in that: The inflation assembly includes an air chamber (401) installed on the sealing plug (301), an air inlet pipe (402) with one end connected to the air chamber (401), an upper shaft plug (403) movably connected in the air chamber (401), a return spring (404) installed in the air chamber (401), and an air outlet pipe (405) with one end connected to the air chamber (401). The upper shaft plug (403) divides the air chamber (401) into two independent spaces. The other end of the air inlet pipe (402) is connected to the airtightness detector (1). Gas flows between the airtightness detector (1) and one independent space in the air chamber (401) through the air inlet pipe (402). One end of the return spring (404) is connected to the inner wall of the air chamber (401), and the other end is connected to the upper shaft plug (403). The other end of the air outlet pipe (405) is connected to the air needle (501). Gas flows between the packaging bag and the other independent space in the air chamber (401) through the air outlet pipe (405) and the air needle (501). When gas flows into one independent space in the air chamber (401) through the air inlet pipe (402), the upper shaft plug (403) moves downward and controls the gas in the other independent space in the air chamber (401) to flow into the packaging bag through the air outlet pipe (405) and the air needle (501).

4. The device for detecting the airtightness of the sealing of a packaging bag according to claim 3, characterized in that: The counterweight assembly includes a clamping plate (601) detachably mounted on the packaging bag and a counterweight block (602) mounted on the clamping plate (601). The gravity of the counterweight block (602) is greater than the buoyancy of the packaging bag.

5. The device for detecting the airtightness of the sealing of a packaging bag according to claim 4, characterized in that: The liquid filling assembly includes a liquid cavity (701) mounted on the sealing plug (301), a lower shaft plug (702) movably connected in the liquid cavity (701), an infusion tube (703) with one end connected to the liquid cavity (701), and an electric valve (704) mounted on the infusion tube (703). The lower shaft plug (702) divides the liquid cavity (701) into two independent spaces. The other end of the infusion tube (703) is connected to the counterweight block (602). The lower shaft plug (702) is fixedly connected to the upper shaft plug (403). The upper shaft plug (403) is used to drive the lower shaft plug (702) to move within the liquid cavity (701). The electric valve (704) is used to open or close the infusion tube (703). The counterweight liquid flows through the infusion tube (703) in one of the independent spaces of the counterweight block (602) and the liquid cavity (701). When the upper shaft plug (403) drives the lower shaft plug (702) to move downward, the counterweight liquid flows into the counterweight block (602) through the infusion tube (703).

6. The device for detecting the airtightness of the sealing of a packaging bag according to claim 5, wherein: A pressing assembly is mounted on the gas filling assembly. An air hood (901) and a reflux assembly are mounted on the top cover assembly. The reflux assembly is in communication with the air hood (901) and the liquid filling assembly. The pressing assembly is used to control the flow of gas between the air hood (901) and the reflux assembly. A positioning assembly is movably connected to the top cover assembly. The liquid return assembly is used to drive the positioning assembly to move in a preset direction. When the airtightness detector (1) inputs gas into the gas filling assembly, the pressing assembly controls the gas in the air hood (901) to flow into the reflux assembly, and the reflux assembly drives the positioning assembly away from the center of the packaging bag. When the airtightness detector (1) extracts gas from the gas filling assembly, the pressing assembly controls the gas in the reflux assembly to flow into the air hood (901), and the reflux assembly drives the positioning assembly closer to the center of the packaging bag. The pressing assembly includes a traction frame (801) fixedly connected to the upper shaft plug (403) and a pressing plate (802) fixedly connected to the traction frame (801). The upper shaft plug (403) controls the pressing plate (802) to move in a preset direction through the traction frame (801).

7. The device for detecting the airtightness of the sealing of a packaging bag according to claim 6, characterized in that: The reflux assembly comprises an air cylinder (1001) mounted on a baffle (303), an air supply pipe (1002) and an air return pipe (1003) connected to the air cylinder (1001) at one end, and a plunger (1004) movably connected to the air cylinder (1001). The plunger (1004) divides the air cylinder (1001) into two independent spaces. The other end of the air supply pipe (1002) is connected to the air hood (901), and the other end of the air return pipe (1003) is connected to the liquid chamber ( 701), the gas flows in an independent space between the gas hood (901) and the gas cylinder (1001) through the gas supply pipe (1002), and the gas flows in another independent space between the liquid cavity (701) and the gas cylinder (1001) through the gas return pipe (1003). When the gas flows in an independent space between the gas hood (901) and the gas cylinder (1001) through the gas supply pipe (1002), the plunger (1004) moves in the gas cylinder (1001).

8. An apparatus for detecting the airtightness of the seal of a packaging bag according to claim 7, characterized in that: A slide groove (1101) is provided on the baffle (303), and a positioning assembly is movably connected in the slide groove (1101). The positioning assembly includes a slider (1102) movably connected in the slide groove (1101), a hanger (1103) fixedly connected to the slider (1102) and a positioning rod (1104) fixedly connected to the hanger (1103). The slider (1102) is fixedly connected to a corresponding plunger (1004). The plunger (1004) is used to drive the slider (1102), the hanger (1103) and the positioning rod (1104) to move along the axial direction of the slide groove (1101).

9. The device for detecting the airtightness of the sealing of a packaging bag according to claim 8, characterized in that: A sensor is installed on the inflatable component, and a fill light (1301) is installed on the top cover component. The sensor is used to detect the state of the inflatable component and send a signal to the control unit of the fill light (1301) and the air tightness detector (1); The sensor comprises a tension sensor (1201) mounted on the upper shaft plug (403), the tension sensor (1201) being used to detect the tension value of the reset spring (404), and when the tension sensor (1201) detects that the tension value of the reset spring (404) reaches a preset value, the airtightness detector (1) is turned off and the fill light (1301) is turned on.

10. A method for detecting the airtightness of the seal of a packaging bag, characterized in that: The device for detecting the air tightness of a packaging bag seal according to claim 9 comprises the following steps: S1: The user pours clean water whose turbidity meets the test requirements into the liquid tank (2) through the water inlet pre-set on the sealing plug (301) until the water level of the clean water is higher than the height of the baffle (303); S2: The sealing plug (301) and the baffle (303) are taken out from the liquid bin (2), and then the clamping plate (601) is clamped and fixed to the bottom of the packaging bag. Then, the air needle (501) is inserted into the packaging bag and the sealing sheet provided on the air needle (501) is bonded to the packaging bag to seal the insertion point; S3: With the sealed portion of the packaging bag facing upward, place the packaging bag together with the counterweight (602) into the liquid cylinder. At this time, the gravity of the counterweight (602) is greater than its own buoyancy and the buoyancy of the packaging bag. The packaging bag sinks underwater under the action of the gravity of the counterweight (602); S4: Reinstall the sealing plug (301) and the baffle (303) into the liquid storage chamber (2), and align the positioning rod (1104) with both sides of the packaging bag to restrict the packaging bag from swinging to both sides under the action of buoyancy. At this time, there is an appropriate height difference between the baffle (303) and the sealed part of the packaging bag; S5: According to the airtightness detection test standard of the packaging bag, set the corresponding parameters on the airtightness detector (1), start the airtightness detector (1), and input gas into one of the independent spaces in the air chamber (401) through the air inlet pipe (402), so that the upper shaft plug (403) moves downward against the elastic force of the return spring (404), and pushes the gas in the other independent space in the air chamber (401) into the air needle (501) through the gas delivery pipe (405), and then flows into the packaging bag through the air needle (501), causing the packaging bag to inflate and expand, and at the same time the buoyancy received by the packaging bag also increases accordingly; S6: Synchronously with S5, the upper shaft plug (403) drives the lower shaft plug (702) to move downward at the same time. The lower shaft plug (702) pushes the counterweight liquid in one of the independent cavities in the liquid chamber (701) into the counterweight block (602) through the liquid delivery pipe (703), and the weight of the counterweight block (602) increases synchronously to resist the increased buoyancy of the packaging bag; S7: Synchronously with S5 and S6, the pressing plate (802) moves downward synchronously under the drive of the upper shaft plug (403), and generates a squeezing force on the air hood (901), so that the gas in the air hood (901) flows into one of the independent spaces in the air cylinder (1001) through the air delivery pipe (1002), causing the plunger (1004) to move, and through the connection with the slider (1102), controlling the hanging bracket (1103) and the positioning rod (1104) to move along the axis direction of the sliding groove (1101), away from the center of the packaging bag, and the gas in the other independent space in the air cylinder (1001) flows into the other independent cavity in the liquid chamber (701) through the air return pipe (1003); S8: When the gas pressure in the packaging bag reaches the preset detection pressure, the tension sensor (1201) detects that the tension value of the return spring (404) reaches the preset value F1, sends a signal to the airtightness detector (1) to stop injecting gas, and sends a signal to the control unit of the supplementary light (1301), and the supplementary light (1301) is turned on to illuminate the packaging bag and the water body in the liquid storage chamber (2); S9: Observe whether there are bubbles generated at the sealed position of the packaging bag. After a period of time, if there are no bubbles generated, the packaging bag meets the airtightness standard. If there are bubbles generated, it does not meet the airtightness standard.

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